Spring for exhaust-valves and the like.



G. T. HUBER.

SPRING FOR EXHAUST VALVES AND THE LIKE.

APPLICATION FILED FEB. I. HHS.

Patented May 6, 1919.

lUNllTFD STATES PATENT GEORGE T. HUBER, OF GLOUCESTER, MASSACHUSETTS,ASSIGNOR OF ONE-HALF TO ABBOTT S. COFFIN, OF GLOUCESTER,

MASSACHUSETTS.

SPRING FOR EXHAUST-VALVES AND THE LIKE.

Specification of Letters Patent.

Patented May 6, 1919.

Application filed February 1, 1918. Serial No. 214,995.

To all whom it may concern Be it known that I, GEORGE T. HUBER, citizenof the United States, residing at Gloucester, in the county of Essex andState of Massachusetts, have invented new and useful Improvements inSprings for Exhaust- Valves and the like, of which the following is aspecification.

This invention relates to improvements in springs for exhaust valves andthe like. It has been developed especially for exhaust valves ofinternal combustion motors such as are used in aviation, but it has anobvious application to other places. In aeroplane motors, where thequantity of heat and the temperature of the out-flowing gases is suchthat the region of the stem of the exhaust valve becomes of hightemperature it has been found that after a time a spring coiled aroundthe valve stem in the ordinary man ner loses its resiliency and fails todo its work properly in the operation of the valve. Attempts to remedythis have been made by using a spring in which the resiliency is derivedfrom a coil located at one side of the valve stem. But such a springproduces serious wear of the stem bearings, and has other bad results.Notwithstanding its. defects, however, it is the best spring hithertoknown so far as I am aware, for places where the special diflicultiesabove stated exist. The object of the present invention is to provide aspring whose resilient parts are safe against injury by the excessiveheat of the exhaust, and whose efl'ort as a spring is applied in thedirection of and at the axis of the valve stem.

One embodiment of the invention is illustrated in theaccompanyingdrawings, but the invention may bepractised in other ways.It is intended that the patent shall coverby suitable expression in theappended claims whatever features of patentable novelty exist in theinvention disclosed.

In the accompanying drawings Figure l is a side elevation of a part ofan exhaust valve, representing somewhat conventionally the casing of anexhaust valve with its stem and with th spring applied thereto;

2. It is a part of the Fig. 2 is a plan of the spring of Fig. 1 on alarger scale;

Fig. 8 is a side elevation not under tension;

Fig. 4 is a plan of a modified form;

Fig. 5 is a side elevation of the form shown in Fig. 4; and

Fig. 6 is a perspective view of a detail of the form shown in Fig. 4.

Referring to the drawings, 10 indicates a valve stem which passesthrough a casing 11 having heat radiating ridges 12. The stem has a head13 consisting of a washer held down by a nut 14 with check nut. Thefunction of the spring is to press upward on the head 13, thusmaintaining the valve closed except when the spring is overborne by asuperior force such as a cam, not illustrated, which depresses the stem10 and so opens the exhaust valve. The objects of the invention areaccomplished by making the spring of such a construction that itsnecessary resiliency is obtained from two coils, 15, 15, arranged at adistance from the stem 10 and symmetrically with respect thereto, madeof Wire and so formed that the wires, which pass on opposite sides ofthe stem, cannot spread under the stress of action. Th coils are alikein size and power, and in distance from the valve stem 10. They arefixed on opposite sides of the stem. There are four of said coils, asrepresented in the drawing, and seen clearly in Figs. 2 and 4, two beingat each side; and the wire which constitutes the whole spring is made intwo pieces, which as a whole are designated by numerals 21 and 22.pieces have portions of the same spring These two 7 marked respectivelyb, a, a 6 and Z2 a a 6 They are symmetrical with respect to each otherabout the axis passing through the valve stein and passing mediallybetween the coils at each end. indicated at m-0c, Fig. invention toprovide means by which these two wires are prevented from spreading fromeach other at the valve stem and are kept so closely together as alwaysto engage that head and to press it along the line of its own axis andwith a combined or unified efiect. This is acco'm pli'she'd, in the formillustrated in Figs. 1, 2

and 3, by making a bow or bond 16 in each wire at the place where it isto pass the valve stem, so that it curves around that stem, one wire 21,passing on one side of it and the other wire, 22, pasisng on the otherside of it, and then to twist together these wires between this yoke andtheir respective coils. One effect of such a twist is that it preventstheir spreading at the yoke where they together surround the stem of thevalve. Another effect is to transfer to the line of the cross axis, andto distribute uniformly over both branches of the yoke at the valvestem, the pressures which are exerted by the respective coils. If theexpansive pressure between one pair of arms a, b, Fig. 2, for example,happens to be stronger than that between the arms a 6 neverthelessthe-tension of this pair of arms is applied to the arm a before itreaches the valve stem head 13. And in turn any tension emanating fromfrom arms a 6 is transferred to the wire a so that, owing to the twistedportion, these two wires (0 and a press upward on the head 13 with equalforce at the yoke 16 assuming of course that this yoke where they passthe stem is set straight. The same is true of the arms a and a Theeffect on the valve stem therefore is applied as a force acting in astraight line, coinciding with its own axis. As it may be inclosed onall sides by the wires, rather closely, it may be guided withconsiderable accuracy. In consequence, the valve is drawn straight uponits seat, instead of there being a tendency to cant it as in the bestheat-guarded springs heretofore known to me, and without the lateralfric tion of stem guide which results when there is such a sidewisepressure on the stem. The spring thus made consists of two parts, eachof which is easily manufactured, and which can be twisted after beingput together. The making of the spring with four wire elementsprojecting from the stem permits the use of relatively small wire. As aresult the wire is more easily worked, because heavy wire has heretoforebeen necesasry; the re siliency can be designed with greater precisionaccording to the actual need, and the spring can be constructed ofproperly graduated size.

The form illustrated in Figs. 1, 5 and 6 is one in which two portions21', 22' are fastened together without the twist, there being a metallicclip 20 which has prongs adapted to be bent around the two elements 0, 0of the wires 21 and 22, which lie parallel with each other so as toprevent their spreading, and which also has a sufficiently broad prong20' adapted to be bent down into the hole of the yoke 16 to engage thetwo wires 0 and c therein and so prevent the clip it self from slippingback away from the yoke. Such bending of the clip can be done bymachinery, so that however heavy the wire thev two parts of the springcan be easily held rigidly together, without introducing the sharp bendthat is involved in the complete twist illustrated in Figs. 1, 2 and 3.In this construction, it is more necessary that the tension of the wires0 d, and that of the wires 0 and (Z be equal; but this is fairly easy toaccomplish because the parts are of such simple and symmetrical shape.

The coils in both cases are shown as equal in size and strength andopposite or balanced in distance and angular location with respect tothe stem, because this is the arrangement that I deem best; but itappears that variations from this particular construction might be madewithout departing from the general idea and principle of the invention.As the stem is inclosed rather closely on all sides by the wires thatare bent around it, it is feasible to make the parts that contact withthe head 13 of equal elevation, so that the resultant pressure upon itis in direction of the axis, even in cases where an arrangementdifferent from that illustrated is used.

I claim as my invention:

1. A spring for valves and the like, comprising a central portionadapted to engage a valve stem, other portions symmetrical with respectto the valve stem and adapted to engage the casing of said stem, springportions on opposite sides of the stem at a distance therefrom, andelements extending from the said spring portions to said central andother portions and applying approximately equal pressure to the centralportion.

2. A spring for valves and the like, comprising wires formed with acentral portion and with spring coils at a distance therefrom; thecentral portion being shaped to engage a valve stem, and the coils beingarranged on different sides thereof, and being of such strength,distance, and direction that in combination they produce a thrustapproximately in the direction of the axis of the stem.

3. A spring for valves and the like, comprising two wires, severallyhaving separated spring coils adapted to be on different sides of avalve stem and parts projecting therefrom which at a. distance therefromare bowed so as jointly to inclose the valve stem closely on all sides.

4. A spring for valves and the like, comprising two wires havingportions twisted together and thereby holding each other from spreading,and having portions thus held that are adapted for fitting around avalve stem, and having spring coils on different sides of and at adistance from said stem.

5. A spring for valves and the like, comprising two wires shaped to fitaround a valve stem and each having spring coils at a distance therefromon opposite sides thereof; the coils of each. wire being besidethecorresponding coils of the other Wire; and the portions of each Wirebetween its coils lying beside and fast to the like portions of theother Wire and including its part of said shape which fits a valve stem.

6. A Composite spring for valves and the like comprising two Wires lyingapproximately in parallelism with their middle portions engagedtogether, and adapted to extend past and engage a valve stem; each ofsaid Wires having its end portions on opposite sides of the middleportion, and having spring coils on opposite sides of the middleportions between its said middle and end portions.

Signed by me at Gloucester, Massachusetts, this 22d day of January,1918.

GEORGE T. HUBER.

Witnesses:

ALBERT BROWN, FRED A. SHACKELFORD.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

